He definitely has commented on Sarkeesian, and critiques some elements of feminism, a few of whom richly deserve it. That's not an area I'm particularly interested in, and I've not followed his videos there.

His critiques of poorly-conceived technological concepts, in particular the "Solar Freakin' Roadways" scam, and Hyperloop, strike me as largely on-mark (if repetitious and self-rightous).

I'm not familiar with any Nazi or other associations, though that would be most unfortunate.

RationalWiki addresses some of this:

http://rationalwiki.org/wiki/Thunderf00t

It has no bearing on the technical criticisms addressed above, however.

His comments on Anita Sarkeesian are creepy and obsessive. Let alone the fact he blatantly and deceptively edits her videos to make his point. https://www.youtube.com/watch?v=7bVqfQvXP2o .

If he's dishonest (not that he's wrong, but that he's dishonest) about basic social studies why should I trust his science? Let alone his experimental results? To be fair he recently disassociated himself from the alt-right ("not") nazis. So there is that at least.